world_blocks_cpp/simplexnoise.h at master · EthanNote/world_blocks_cpp · GitHub

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#pragma once
#include<memory>
#include<math.h>

// http://webstaff.itn.liu.se/~stegu/simplexnoise/SimplexNoise.java

class Grad
{
public:
	double x, y, z, w;

	Grad(double x, double y, double z)
	{
		this->x = x;
		this->y = y;
		this->z = z;
	}

	Grad(double x, double y, double z, double w)
	{
		this->x = x;
		this->y = y;
		this->z = z;
		this->w = w;
	}
};

class CSimplexNoise {  // Simplex noise in 2D, 3D and 4D
private:
	Grad grad3[12] = {
		Grad(1,1,0), Grad(-1,1,0), Grad(1,-1,0), Grad(-1,-1,0),
		Grad(1,0,1), Grad(-1,0,1), Grad(1,0,-1), Grad(-1,0,-1),
		Grad(0,1,1), Grad(0,-1,1), Grad(0,1,-1), Grad(0,-1,-1)
	};

	Grad grad4[32] = {
		Grad(0,1,1,1),  Grad(0,1,1,-1),  Grad(0,1,-1,1),  Grad(0,1,-1,-1),
		Grad(0,-1,1,1), Grad(0,-1,1,-1), Grad(0,-1,-1,1), Grad(0,-1,-1,-1),
		Grad(1,0,1,1),  Grad(1,0,1,-1),  Grad(1,0,-1,1),  Grad(1,0,-1,-1),
		Grad(-1,0,1,1), Grad(-1,0,1,-1), Grad(-1,0,-1,1), Grad(-1,0,-1,-1),
		Grad(1,1,0,1),  Grad(1,1,0,-1),  Grad(1,-1,0,1),  Grad(1,-1,0,-1),
		Grad(-1,1,0,1), Grad(-1,1,0,-1), Grad(-1,-1,0,1), Grad(-1,-1,0,-1),
		Grad(1,1,1,0),  Grad(1,1,-1,0),  Grad(1,-1,1,0),  Grad(1,-1,-1,0),
		Grad(-1,1,1,0), Grad(-1,1,-1,0), Grad(-1,-1,1,0), Grad(-1,-1,-1,0)
	};

	short p[256] = { 151,160,137,91,90,15,
	131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
	190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
	88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
	77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
	102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
	135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
	5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
	223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
	129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
	251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
	49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
	138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 };
	// To remove the need for index wrapping, double the permutation table length
	short perm[512];
	short permMod12[512];
	void init() {
		for (int i = 0; i < 512; i++)
		{
			perm[i] = p[i & 255];
			permMod12[i] = (short)(perm[i] % 12);
		}
	}

	// Skewing and unskewing factors for 2, 3, and 4 dimensions
	double F2 = 0.5*(sqrt(3.0) - 1.0);
	double G2 = (3.0 - sqrt(3.0)) / 6.0;
	double F3 = 1.0 / 3.0;
	double G3 = 1.0 / 6.0;
	double F4 = (sqrt(5.0) - 1.0) / 4.0;
	double G4 = (5.0 - sqrt(5.0)) / 20.0;

public:
	CSimplexNoise();

	// This method is a *lot* faster than using (int)Math.floor(x)
	static int fastfloor(double x);

	static double dot(Grad & g, double x, double y);

	static double dot(Grad & g, double x, double y, double z);

	static double dot(Grad & g, double x, double y, double z, double w);


	// 2D simplex noise
	double noise(double xin, double yin);


	// 3D simplex noise
	double noise(double xin, double yin, double zin);


	// 4D simplex noise, better simplex rank ordering method 2012-03-09
	double noise(double x, double y, double z, double w);


};